Needle thread take-up for double chain stitch sewing machines



E. ANGELE Feb. 13, 1968 NEEDLE THREAD'TAKEUP FOR DOUBLE CHAIN STITCH SEWING MACHINES Filed Oct. 22, 1965 INVENTOR EUGEN ANGELE mwewafim United States Patent 3568,5138 NEEDLE THREAD TAKE-UP FUR DQUBLE CHAEN STITCH SEWING MACHKNES Eugen Angele, Stuttgart, Wurttemberg, Germany, assignor to Union Special Maschinenfabrilr, G.m.b.H., Stuttgart,

Wurttemberg, Germany Filed Get. 22, M65, Ser. No. 501,257 Claims. ((11. 112-245) ABSTRAQT OF THE DESCLOSURE A needle thread take-up device is provided, adapted to be carried by a vertically movable needle bar, the device including thread guide means in the form of horizontally spaced members with thread-receiving eyelets therein, and a torsion spring carried between the horizontally spaced members, with a free end of the spring adapted to engage and tension thread carried between the eyelets. The vertical movement of the spring, in cooperation with the vertical movement of the needle bar facilitates the desired tensioning during ascent and descent of the needle, for facilitating the desired take-up of the thread, thereby using the inertia forces operative upon the free end of the spring to advantage.

The invention concerns a needle thread take-up for a double chain stitch sewing machine, wherein take-up components reciprocating or swinging in rhythm with the needle bar move relative to the thread eyelets and takeup wire means mounted fixedly on the machine frame.

In the case of such needle thread take-up devices, the parts fixed to the frame are adjusted in relation to the reciprocating or swinging parts in such a manner, that the needle thread will remain essentially under tension during the whole up and down movement of the needle. However, when the needle rises from its low position, the needle thread becomes loose or slack for a short time in order to form a loop for the entry of the looper, as is well known in the art.

The regulation of the size of the needle thread loop formation has, until now, been difiicult in the case of hitherto used thread take-up devices for double chain stitch sewing machines, since the size of the needle thread loop, forming during the ascent of the needle from its low point, will depend upon the quantity of thread drawn off, the said thread being drawn off through the thread takeup device during the descent of the needle from the needle plate to the low position, as is well known.

It is an object of the present invention to regulate the size of the needle thread loop, independently of the thread takes-up devices during the descent of the needle from the chain stitch sewing machines having take-up parts moving swingingly or in reciprocation in rhythm with the needle bar and relatively to stationary thread eyelets and take-up wires on the frame.

Essentially this object will be achieved by reason of the fact that within the area of the cooperating take-up parts, preferably on one of the swinging or reciprocating parts, a spring engaging the thread has been arranged and tensioned in such a manner, that it will serve to draw off loose needle thread and then again release it When the thread is being tensioned. A preferred design consits of the following: that the thread guide placed on the upper end of the needle bar will carry the spring; that the thread guide has been equipped with two legs, each leg containing an eyelet, the spring engaging the needle thread between said legs; that a bolt has been screwed into the thread guide which carries a torsion spring having a free end and being adjustable as to tension; that an adjustable stop means has been provided which limits the path of motion of the free end of the spring, and that the adjustable stop means has been mounted on the bolt carrying the spring.

The size of the needle thread loop, which is formed during the ascent of the needle from its low position, can be regulated advantageously through this spring, said spring acting on the needle thread and being adjustable as to tension and the extent of its path of movement. During the preceding pulling up of the needle thread loop, at the time that the needle thread leaves the looper point during the descent of the needle, it can be seen that too much needle thread may be taken oh, so that during the return of the needle an overly large needle thread loop will be formed. In this case, the spring, tensioned during the pulling-off of the needle thread, will take up a part of the thread from the needle thread loop, by relaxing. This quantity of thread taken up by the spring can be determined by an adjustable stop which limits the path or extent of movement of the free end of the spring The force of the spring itself is likewise adjustable, in order to adapt it to the tension imparted to the thread through the thread tensioning discs, the arrangement being such that the spring will be tensioned during the descent of the needle and will act gently as an auxiliary take-up on the thread during the ascent of the needle and pulling oil of the thread.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 shows a schematic presentation of the thread feeding in the case of double chain stitch sewing machines;

FIGURE 2 shows the thread guide, to be placed on the needle bar, viewed from the side, parts being in vertical cross section.

FIGURE 3 shows the thread guide, viewed from above, parts being in horizontal section.

In a double chain stitch sewing machine according to FIGURE 1 the needle thread It is to be considered as fed in the well known manner through thread tension disc means (not shown) and via an adjustable eyelet 2 fixed on the frame to a take-01f finger 3 reciprocating in the rhythm of the needle bar. From there thread 1 runs through a thread guide 5, placed on the needle bar 4, which acts together with a take-up wire 6, fixed on the frame, down to the eye '7 of the needle 8. The needle 8 acts cooperatively, in the well known manner of stitch forming, with an oscillating looper 11, carrying a looper thread 10.

According to this present invention, the thread guide 5 is secured on and is movable with the needle bar 4, as indicated in FIGURE 1. This feed thread guide 5 has the shape of a bar that is bent back or otherwise shaped to form two parallel horizontally spaced legs 12 and 13 each of which is equipped with a thread eye 14. A bolt 15 having thereon a collar 16 is screwed into or otherwise mounted on the thread guide 5. This bolt 15, on the side of the collar 16, carries a disc 1'7, which is equipped with a projection 18, as illustrated in FIGURES 2 and 3, acting as a stop, when engaged by the spring 23, said disc being secured against the collar as by a nut 19. On the other side, the bolt 15 carries a casing or sleeve 20. A torsion spring 21 is wound around the casing 20 and is fixed on the casing at one end as at 22, the other or free end 23 of the spring reaching between the legs 12, 13 of the thread guide 5 as clearly illustrated in FIGURE 3. The casing 20 is arranged for rotational adjustment on the bolt 15, thereby to elfect regulation of the tension of the spring 21. A conical nut 25 threaded onto the bolt 3 serves as a means for securing the casing or sleeve in the desired adjusted position. It will be apparent also that by a loosening of the nut 19, turning of the disc 17 about the bolt 15 and retightening of the nut, desired adjustments of the position of the spring placement stop 18 can be effected and secured.

The bracket or mounting eye 24 formed on the thread guide 5 is provided to facilitate mounting of the guide atop the needle bar 4 as shown in FIGURE 1.

It should be apparent from the foregoing that the needle thread 1 after leaving the eye of the reciprocatory take-otf finger 3 passes over the horizontally spaced arms of the take-up wire 6 and through the horizontally aligned eyes 14 in the horizontally spaced legs 12 and 13 of the thread guide 5, passing under the raised and downwardly tensioned free end of the spring 23 as will be apparent by reference to the illustration in FIGURE 1, and the full line position illustrated in FIGURE 2. From the thread guide 5 andthe arms of the take-up wire 6 as viewed in FIGURE'I, the needle thread 1 passes down and through the needle eye 7.

The size of the needle thread loop, which is formed in the well known manner during the ascent of the needle from its low position (FIGURE 1), can be regulated advantageously through action of the spring 23, said spring being adjustable as to tension and the extent of its path of movement in the manner previously described.

During the preceding pulling up of the needle thread loop at the time that the needle thread leaves the looper point during the descent of the needle, it can be seen that too much needle thread may be taken off, so that during the return of the needle an overly large needle thread loop will be formed. In this case the spring 23, tensioned during the pulling off of the needle thread as evidenced by its full line position in FIGURE 2, will take up a part of the thread from the needle thread loop, by relaxing to the dotted line position against the stop 18. The adjusted position of said stop determines the extent of this take up.

The force of the spring 23 itself is likewise adjustable in the manner previously described, namely by rotational adjustment of the sleeve 20 and the spring anchor point 22 about the bolt 15, in order to adapt this spring equipment to the tension imparted to the thread through the conventional tensioning discs, the arrangement being such that the spring will be tensioned during the descent of the needle and will act gently as an auxiliary take-up on the thread during the ascent of the needle and pulling off of the thread.

While preferred part form and arrangement has been disclosed herein, it is to be understood that variations in such form and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A thread take-up means mountable on the needle bar of the double chain stitch sewing machine, said takeup means comprising a body having at one end horizontally extending connection means for removable attachment atop a vertically disposed needle bar, and at its other end generally parallel horizontally opposing legs having horizontally cross aligned needle thread guide eyelets formed therein, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets, there also being included stop means for limiting movement of said free end portion.

2. The device of claim 1, wherein said stop means is adjustable.

3. A thread take-up means mountable on the needle bar of a double chain stitch sewing machine, said take-up means comprising a body having at one end horizontally extending connection means for removable attachment atop a vertically disposed needle bar, and at its other end generally parallel horizontally opposing legs having horizontally cross aligned needle thread guide eyelets formed therein, a bolt transversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets, there also being included stop means for limiting movement of said free end portion, means for varying the tension of the spring means, and means for varying the position of the stop means.

4. A thread take-up means mountable on the needle bar of a double chain stitch sewing machine, said takeup means comprising a body having at one end horizontally extending connection means for removable attachment atop a vertically disposed needle bar, and at its other end generally parallel horizontally opposing legs having horizontally cross aligned needle thread guide eyelets formed therein, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets, there also being included stop means for limiting movement of said free end portion, and means for varying the tension of the spring means including a sleeve surrounding and turnable on the bolt and having provision thereon for anchoring the coiled portion of the spring and means for adjusting the position of the sleeve on the bolt.

5. A thread take-up means mountable on the needle bar of a double chain stitch sewing machine, said takeup means comprising a body having at one end horizontally extending connection means for removable attachment atop a vertically disposed needle bar, and at its other end generally parallel horizontally opposing legs having horizontally cross aligned needle thread guide eyelets formed therein, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets, there also being included stop means for limiting movement of said free end portion, means for varying the tension of the spring means, and means for varying the position of the stop means, said stop means comprising a disk carried by and turnable about the bolt and a stop member projecting from said disk, and said stop position varying means including means for securing the disk at adjusted positions on said bolt.

6. In a double chain stitch sewing machine the combination of a reciprocable needle bar and needle, a cooperating looper, a needle thread supply means including stationarily supported thread eyelet means, a needle thread take-up means movable in timed relation to the needle bar, and a needle thread take-up means mounted on and movable with the needle bar and comprising a body having at one end means providing removable attachment atop a generally vertical needle bar, and at its other end generally parallel opposing legs having horizontally cross aligned needle thread guide eyelets formed therein for receiving therethrough needle thread from the needle thread take-up means movable in timed relation to the needle bar, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets for engagement with the needle thread where it passes through said eyelets on its way to the needle, there also being included stop means for limiting movement of said free end portion.

7. The combination of claim 6, including a generally horizontally disposed stationary take-up wire positioned adjacent the thread take-up means which is mounted on the needle bar.

8. In a double chain stitch sewing machine the combination of a reciprocable needle bar and needle, a cooperating looper, a needle thread supply means including stationarily supported thread eyelet means, a needle thread take-up means movable in timed relation to the needle bar, and a needle thread take-up means mounted on and movable with the needle bar and comprising a body having at one end means providing removable attachment atop a generally vertical needle bar, and at its other end generally parallel opposing legs having horizontally cross aligned needle thread guide eyelets formed therein for receiving therethrough needle thread from the needle thread take-up means movable in timed relation to the needle bar, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets for engagement with the needle thread where it passes through said eyelets on its way to the needle, there also being included stop means for limiting movement of said free end portion, means for varying the tension of the spring means, and means for varying the position of the stop means.

9. In a double chain stitch sewing meachine the combination of a reciprocable needle bar and needle, a cooperating looper, a needle thread supply means including stationarily supported thread eyelet means, a needle thread take-up means movable in timed relation to the needle bar, and a needle thread take-up means mounted on and movable with the needle bar and comprising a body having at one end means providing removable attachment atop a generally vertical needle bar, and at its other end generally parallel opposing legs having horizontally cross aligned needle thread guide eyelets formed therein for receiving therethrough needle thread from the needle thread take-up means movable in timed relation to the needle bar, a bolt traversing the body between the attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending between said legs and movable in a generally vertical plane across the space between the eyelets for engagement with the needle thread where it passes through said eyelets on its way to the needle, there also being included stop means for limiting movement of said free end portion, and means for varying the tension of the spring means including a sleeve surrounding and turnable on the bolt and having means thereon for anchoring the coiled portion of the spring and means for adjusting the position of the sleeve on the bolt.

10. In a double chain stitch sewing machine the combination of a reciprocable needle bar and needle, a cooperating looper, a needle thread supply means including stationarily supported thread eyelet means, a needle thread take-up means movable in timed relation to the needle bar, and a needle thread take-up means mounted on and movable with the needle bar and comprising a body having at one end means providing removable attachment atop a generally vertical needle bar, and at its other end generally parallel opposing legs having horizontally cross aligned needle thread guide eyelets formed therein for receiving therethrough needle thread from the needle thread take-up means movable in timed relation to the needle bar, a bolt traversing the body between the.

attaching means and said legs, and a tensioned spring means supported on the bolt, wherein the spring means is a torsion spring having a portion coiled about the bolt and a free end portion extending'between said legs and movable in a generally vertical plane across the space between the eyelets for engagement with the needle thread where it passes through said eyelets on its way to the needle, there also being included stop means for limiting movement of said free end portion, said stop means comprising a disk carried by and turnable about the bolt and a stop member projecting from said disk, and said stop position varying means including means for securing the disk at adjusted positions on said bolt.

References Cited UNITED STATES PATENTS 1,166,834 1/191'6 Hemleb 112-245 1,370,528 3/1921 Fossa 112-241 X 1,808,506 6/1931 Pierce 112-241 2,496,117 1/1950 Boyer 112254 608,795 8/1898 Richards 112254 2,496,116 1/1950 Boyer 112254 JORDAN FRANKLIN, Primary Examiner.

G. H. KRIZMANICH, Assistant Examiner. 

